This application contains a four-year research training program for the development of an academic career in physiology and medicine. The candidate completed an emergency medicine residency at the University of Massachusetts Medical School in 2002 and has continued to perform research, teaching and clinical duties at the university. The described training program is designed to provide the candidate with the didactic and practical experience necessary for him to become an independent investigator in the field of organophosphate physiology. The scientific aims of this investigation focus on characterizing the central nervous system physiologic effects of organophosphorus compounds. The candidate has chosen Dr. Craig F. Ferris Ph.D. as a mentor for this project. As Director of the Center for Comparative Neuro-lmaging at the university, Dr. Ferris has extensive experience in CNS physiology and functional magnetic resonance imaging (fMRI). To further augment his training, the candidate will meet regularly with a respiratory neurologist and a biophysicist at his institution. The candidate's research efforts will focus on determining the mechanism by which organophosphorus agents exert their effects on respiration. Specific emphasis will be placed on determining: 1) the respiratory centers' response to organophosphates via fMRI imaging, with and without antidotal treatment; 2) the role of cortical inputs in the respiratory depression; and 3) the role of peripheral signals in modulating respiration. The combined Departments of Physiology and Emergency Medicine at the University of Massachusetts Medical School are an ideal setting for this grant and will provide Dr. Bird with the facilities, equipment and expertise necessary to achieve the goals set forth in this proposal.